Evaluate: $\frac{2}{7} \cdot \frac{5}{9} + \frac{5}{7} \cdot \frac{5}{9}$. Express your answer as a common fraction.
Solution: Factor out $\frac{5}{9}$: \[ \frac{2}{7}\cdot\frac{5}{9}+\frac{5}{7}\cdot\frac{5}{9}=\left(\frac{2}{7}+\frac{5}{7}\right)\frac{5}{9}=1\cdot\frac{5}{9}=\boxed{\frac{5}{9}}. \]